EL PASO COUNTY, Colo. -- The stepmother of a missing Colorado boy who vanished in January was arrested and charged with murder Monday morning, El Paso County Sheriff Bill Elder said in a news conference.

Gannon Stauch, 11, was last seen January 27, the same day his stepmother Leticia Stauch reported him missing.

According to voter registration information, Stauch's stepmother lived in South Carolina most of her life, but did stay for some time in Robeson County, Pembroke and Lumberton. His father has previously lived in North Charleston and Horry County in South Carolina. His biological mother previously lived in Fayetteville and Wilmington in North Carolina.

Leticia Stauch was taken into custody Monday in Myrtle Beach, S.C., Elder said.

Leticia Stauch is charged with first-degree murder of a child under 12 years old by a person in a position of trust, child abuse resulting in death, tampering with a body and tampering with evidence.

Investigators said Gannon Stauch has not been found, but they do not believe he is still alive.

Gannon Stauch's mother, Landen Hiott, called Gannon her hero at Monday's press conference and said she received the worst and best news.

"Obviously, we know what the worst news is," Hiott said through tears. "The best news is that justice will be served. And I'll make sure that justice is served. Because my boy did not deserve any of this."

Leticia Stauch reported her stepson missing on January 27, telling authorities he was last seen at home between 3:15 p.m. and 4:15 p.m. before leaving to walk to a friend's house, according to the El Paso County Sheriff's Department.

In an interview last month with KKTV, Stauch denied having anything to do with her stepson's disappearance.

"I would never, ever, ever hurt this child," she told the station.

Efforts to reach Leticia Stauch or her attorney were unsuccessful.

Gannon was initially reported as a runaway, but on Jan. 30 his disappearance was changed to a missing/endangered persons case.

A neighbor said footage captured by his security camera the day Gannon went missing showed Leticia Stauch driving away with the boy in the morning, and returning hours later alone. Authorities have said they are aware of the footage and have not disputed the neighbor's description, but have described it only as "one piece in a very, very, very large puzzle."

The El Paso County Sheriff's Office said they've gotten more than 800 tips and put in thousands of hours into search efforts that included drones and search dogs.

There are search efforts for Gannon underway at Highway 105 and Highway 83 today. If you have any information regarding Gannon, please call 719-520-6666. #FindGannonpic.twitter.com/osrAgqprkw

Multiple agencies have assisted in the investigation and searches, including the National Center for Missing and Exploited Children, the Colorado Springs Police Department, the FBI Child Abduction Rapid Deployment Team, and Colorado Parks and Wildlife.

Leticia Stauch will remain in custody in South Carolina until she is extradited back to Colorado.